Seasonal rainfall affects the outflow of the Pearl River,the largest river in southern China,causing brackish waters to extend into areas which for most of the year experience clear oceanic waters.

• 华南最大河流珠江所流出的河水，因受季节性的雨水影响，引致咸淡混合的水流，流入全年中大部分时间水质都是清澈的海洋。